The present invention relates to equipment for performing plasma etching of semiconductor devices. More particularly, the present invention relates to the installation of electrode assemblies used in conjunction with such equipment.
As demand has grown for increasingly compact integrated circuit devices, plasma etching has been used to etch patterns on wafers with a high degree of precision. In a typical plasma etching process, a gas in an etching chamber is excited to a plasma state using radio frequency energy. With the wafer placed on an electrode, ions emerging from the plasma are accelerated towards the wafer. When the ions reach the wafer, they etch away surfaces that are not protected by a resist mask.
To realize the potential for high resolution etching using a plasma etching process, it is desirable to maintain a considerable degree of control over certain variables in the process. These variables include, for example, the process temperature, radio frequency power, and the composition of the etching gas. Of particular importance is the precise alignment of the electrode assemblies in the etching chamber.
Conventional electrode alignment techniques, such as visual inspection, have often been characterized by a lack of precision and a lack of repeatability. Accordingly, it has been particularly difficult to align the electrode assemblies consistently and properly. When the electrode assemblies are improperly aligned, poor etch uniformity and particle generation can result.
According to one embodiment, the present invention is directed to a mounting method for mounting an electrode assembly on a plasma etching apparatus. The mounting method includes inserting each of a plurality of alignment pins in a respective one of a plurality of apertures in the plasma etching apparatus. A plurality of apertures in the electrode assembly are aligned relative to the alignment pins. The electrode assembly is then mounted on the plasma etching apparatus, passing the alignment pins through the apertures of the electrode assembly. Each alignment pin is then replaced with a locking arrangement.
Another embodiment of the present invention is directed to an alignment pin for use in mounting an electrode assembly in a plasma etching apparatus. The alignment pin has a slotted head and a tapered body portion. The tapered body portion tapers from a first diameter at the slotted head to a second, larger, diameter at a first distance away from the slotted head. A non-tapered body portion extends from the tapered body portion. A distal end portion is configured to be inserted into a corresponding aperture of the plasma etching apparatus.
The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description that follow more particularly exemplify these embodiments.